Abstract

BUENO-LOPEZ, Santiago Wigberto; GARCIA-LUCAS, Encarnación  and  CARABALLO-ROJAS, Luis Rene. Allometric equations for total aboveground dry biomass and carbon content of Pinus occidentalis trees. Madera bosques [online]. 2019, vol.25, n.3, e2531868.  Epub May 15, 2020. ISSN 2448-7597.  https://doi.org/10.21829/myb.2019.2531868.

Although precise species-specific aboveground tree biomass equations are needed in the Dominican Republic to quantify potential carbon storage in the context of climate change and sustainable forest management, there has been a lack of available information concerning total aboveground biomass and/or carbon content for naturally occurring Pinus occidentalis trees. The objectives of the study were to develop species-specific allometric biomass models for P. occidentalis, as well as to assess variation in carbon concentration among stem plus bark, branches and foliage by means of chemical analyses. Predictor variables included diameter at breast height (DBH) and total tree height (H), alone and in combination. Model fitting methods employing linear and nonlinear regression techniques were used and evaluated based on goodness-of-fit criteria. Two competing biomass models produced similar goodness-of-fit statistics: model 4, fitted by the Weighted Non-linear Least Squares technique, $B_T=2.327x{10}^5{\left({DBH}^{2}H\right)}^{1.006}$, and model 6, fitted by modeling the variance component and applying the Maximum Likelihood method, $B_T=0.00115+2.469x{10}^5{DBH}^{2}H$. Average carbon concentration (%) was highest in foliage tissue (49.8%), followed by branches (46.37%) and, lastly, stem plus bark (45.95%). On average, each individual tree is storing 175 kg of total aboveground carbon. To our knowledge, this is the first account reporting carbon fraction for this tropical species. Calculated wood carbon fractions from the study can be easily incorporated into forest C accounting, and may reduce errors in forest C valuations, which nowadays are performed using global estimates published elsewhere.

Keywords : allometric models; carbon fraction allocation; climate change; tropical conifer species; variance-modeled regression; weighted linear and non-linear regression.